ABSTRACT
Knowing particle penetration efficiencies and concentration distributions in an inlet channel of a sampling device is beneficial for the robust assessment, attribution and quantification of nanoparticles produced by various activities. The aim of this research is to evaluate the effect of the presence or absence of a conical column inside a hollow tapered cylinder on the nanoparticle penetration efficiency and its outlet concentration profile for different flow rates. The particle penetration characteristics of various sizes from 3 nm to 20 nm were numerically investigated by using the flow field and convection diffusion equations within the hollow tapered cylinder. Firstly, the proposed model of the nanoparticle penetration efficiency for the hollow tapered cylinder with the conical column is validated with the experimental data in the literature. Then, the results indicate that the concentration at the outlet of the hollow tapered cylinder with the conical column exhibits annular profiles for 3 nm and 5 nm nanoparticles at a flow rate of 2.0 L/min, which is found to avoid centralizing the particles in the exit area. In addition, the penetration efficiency of nanoparticles can be improved by increasing flow rates or removing the conical column inside the hollow tapered cylinder. Finally, the ring-shaped concentration profile of the 10 nm nanoparticles at the outlet of the hollow conical cylinder with the conical column becomes more obvious as the flow rate decreases. This study interprets and quantitatively decides the nanoparticle penetration efficiency and its exit concentration profile for the hollow tapered cylinder with or without the conical column. Therefore, the results can provide some useful design references for the transport of nanoparticles in the hollow tapered cylinder.
ABSTRACT
Background Healthy aging with dignity and aging in place are important concepts for most Taiwanese individuals, which can hopefully affect health policies. However, many elders have been encouraged to stay at home during the COVID-19 pandemic since January 2020. Consequently, most elders limited their social participation in a previous regular activity in the community center, which undermined the strategies for healthy aging. Few studies have explored how to promote or maintain holistic health and physical fitness for community elders during the COVID-19 worldwide. Therefore, this study aimed to establish and evaluate the impact of an innovative summer camp program for older adults in the rural community.Methods A quasi-experimental pre-post-test design was used. The innovative summer camp (ISC) was based on a standardized protocol of modified Baduanjin exercise combined with three recreation breathing games. Participants were recruited from three community centers around the western coastal Yunlin County between June and August 2020. ISC program was designed and demonstrated by the research team and conducted by each community care worker for 90 minutes per day, five days per week, for 12 weeks. The paired t-test was used to measure the physical biomarkers, pulmonary lung function, and health-related fitness changes.Results Sixty-eight participants completed this study. The findings indicated that the ISC program significantly improved elderly individuals’ physiological biomarkers and health-related fitness, including reduced body weight, waistline, systolic blood pressure, and increased forced vital capacity, biceps arm flexion, sit and stand from a chair, step with a knee up in situ, and stand on one foot with eyes open. Besides wearing a facemask during the activity, almost all participants reported that they felt happy, satisfied and hoped that this program can be continued in their community center.Conclusion This pilot study supported the finding that a three-month ISC program can improve physical biomarkers and health-related fitness. The results strongly suggested that community care workers can employ the proposed ISC program as routine activity for community elders.
Subject(s)
COVID-19ABSTRACT
ABSTRACT Tests that detect the presence of SARS-CoV-2 antigen in clinical specimens from the upper respiratory tract can provide a rapid means of COVID-19 disease diagnosis and help identify individuals that may be infectious and should isolate to prevent SARS-CoV-2 transmission. This systematic review assesses the diagnostic accuracy of SARS-CoV-2 antigen detection in COVID-19 symptomatic and asymptomatic individuals compared to RT-qPCR, and summarizes antigen test sensitivity using meta-regression. In total, 83 studies were included that compared SARS-CoV-2 rapid antigen lateral flow testing (RALFT) to RT-qPCR for SARS-CoV-2. Generally, the quality of the evaluated studies was inconsistent, nevertheless, the overall sensitivity for RALFT was determined to be 75.0% (95% confidence interval [CI]: 71.0-78.0). Additionally, RALFT sensitivity was found to be higher for symptomatic versus asymptomatic individuals and was higher for a symptomatic population within 7 days from symptom onset (DSO) compared to a population with extended days of symptoms. Viral load was found to be the most important factor for determining SARS-CoV-2 antigen test sensitivity. Other design factors, such as specimen storage and anatomical collection type, also affect the performance of RAFLT. RALFT and RT-qPCR testing both achieve high sensitivity when compared to SARS-CoV-2 viral culture.
Subject(s)
COVID-19ABSTRACT
BackgroundThe RT-qPCR assay for detecting SARS-CoV-2 virus is the favorable approach to test suspected COVID-19 cases. However, discordant results can occur when two or more assays are compared. Variability in analytical sensitivities between assays, among other factors, may account for these differences in reporting. MethodsThe limits of detection (LOD) for the BD SARS-CoV-2 Reagents for BD MAX System ("MAX SARS-CoV-2 assay"), the Biomerieux BioFire(R) Respiratory Panel 2.1 ("BioFire SARS-CoV-2 assay"), the Roche cobas SARS-CoV-2 assay ("cobas SARS-CoV-2 assay"), and the Hologic Aptima(R) SARS-CoV-2 assay Panther(R) ("Aptima SARS-CoV-2 assay") RT-qPCR systems were determined using a total of 84 contrived nasopharyngeal specimens with seven target levels for each comparator. The positive and negative percent agreement (PPA and NPA, respectively) for the MAX SARS-CoV-2 assay were compared to the Aptima SARS-CoV-2 assay in a post-market clinical study utilizing 708 paired nasopharyngeal specimens collected from suspected COVID-19 cases. Discordant results were further tested by the cobas and BioFire SARS-CoV-2 assays. ResultsThe measured LOD for the MAX SARS-CoV-2 assay (251 copies/mL) was comparable to the cobas SARS-CoV-2 assay (298 copies/mL) and the BioFire SARS-CoV-2 assay (302 copies/mL); the Aptima SARS-CoV-2 assay had a LOD of 612 copies/mL. The MAX SARS-CoV-2 assay had a PPA of 100% (95%CI: [97.3%-100.0%]) and a NPA of 96.7% (95%CI: [94.9%-97.9%]) when compared to the Aptima SARS-CoV-2 assay. ConclusionsThe MAX SARS-CoV-2 assay exhibited a high analytical sensitivity and specificity for SARS-CoV-2 detection. The clinical performance of the MAX SARS-CoV-2 assay agreed with another sensitive EUA cleared assay.